My toroid is a 18-0-18, Its got 4 secondary leads and 2 primary leads. That was all straight forward, 2 primarys to wall, 1 pair secondaries to 1 rectifier. Now, after rectification, I get the same voltage. It's supposed to go up to like 25v isn't it?

Secondly, I've had the amp working and everything of 38v, but after about 3 seconds the sound just goes distored and so I turn it off. What would cause this? The sound works fine for the first 3 seconds.